Karazhan (a.k.a. Medivh's Tower, Ivory Tower of Karazhan, or Ivory Spire of Karazhan) is an abandoned citadel (or castle) located on a nexus of ley lines in southern Deadwind Pass. The tower is best known for its last known occupant — Medivh, the last Guardian of Tirisfal. After Medivh was killed by Khadgar, Lothar, and Garona, the tower sealed itself off from the rest of the world. But recently, Karazhan has reawakened — an evil presence has taken the tower as its own, its halls crawling with spirits and demons... and Medivh's presence is still alive and well, even decades after his death.
Karazhan, as a level 70 ten-man raid instance, was opened in World of Warcraft: The Burning Crusade.